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Python プラグインの開発


Python plugins are listed together with C++ plugins in QGIS plugin manager. They are searched for in these paths:

  • UNIX/Mac: ~/.qgis/python/plugins and (qgis_prefix)/share/qgis/python/plugins
  • Windows: ~/.qgis/python/plugins and (qgis_prefix)/python/plugins

Home directory (denoted by above ~) on Windows is usually something like C:\Documents and Settings\(user) (on Windows XP or earlier) or C:\Users\(user). Since QGIS is using Python 2.7, subdirectories of these paths have to contain an __init__.py file to be considered Python packages that can be imported as plugins.


By setting QGIS_PLUGINPATH to an existing directory path, you can add this path to the list of paths that are searched for plugins.


  1. アイデア: 新しいQGISプラグインでやりたいことのアイデアを持ちます。なぜそれを行うのですか? どのような問題を解決しますか? その問題のための別のプラグインは既にありますか?

  2. Create files: Create the files described next. A starting point (__init__.py). Fill in the プラグインメタデータ (metadata.txt) A main python plugin body (mainplugin.py). A form in QT-Designer (form.ui), with its resources.qrc.
  3. コードを書く: mainplugin.py 内にコードを記述する

  4. テスト: QGISを閉じて再度開き、あなたのプラグインをインポートします。すべてがOKかチェックして下さい。

  5. Publish: Publish your plugin in QGIS repository or make your own repository as an “arsenal” of personal “GIS weapons”.


Since the introduction of Python plugins in QGIS, a number of plugins have appeared - on Plugin Repositories wiki page you can find some of them, you can use their source to learn more about programming with PyQGIS or find out whether you are not duplicating development effort. The QGIS team also maintains an 公式のpythonプラグインリポジトリ. Ready to create a plugin but no idea what to do? Python Plugin Ideas wiki page lists wishes from the community!


Here’s the directory structure of our example plugin

    __init__.py    --> *required*
    mainPlugin.py  --> *required*
    metadata.txt   --> *required*
    resources.qrc  --> *likely useful*
    resources.py   --> *compiled version, likely useful*
    form.ui        --> *likely useful*
    form.py        --> *compiled version, likely useful*


  • __init__.py = The starting point of the plugin. It has to have the classFactory() method and may have any other initialisation code.
  • mainPlugin.py = プラグインの主なワーキングコード。このプラグインの動作に関するすべての情報と主要なコードを含みます。

  • resources.qrc = The .xml document created by Qt Designer. Contains relative paths to resources of the forms.
  • resources.py = 上記の.qrcファイルがPythonに変換されたもの。

  • form.ui = The GUI created by Qt Designer.
  • form.py = 上記のform.uiがPythonに変換されたもの。

  • metadata.txt = Required for QGIS >= 1.8.0. Containts general info, version, name and some other metadata used by plugins website and plugin infrastructure. Since QGIS 2.0 the metadata from __init__.py are not accepted anymore and the metadata.txt is required.

ここ では典型的なQGISのPythonプラグインの基本的なファイル(スケルトン)をオンラインで自動的に作成することができます。

また、 Plugin Builder と呼ばれるQGISプラグインがあります。QGISからプラグインテンプレートを作成しますがインターネット接続を必要としません。2.0に互換性のあるソースを生成しますので推奨される選択肢です。


If you plan to upload the plugin to the 公式のpythonプラグインリポジトリ you must check that your plugin follows some additional rules, required for plugin 検証




まず、プラグインマネージャーは名前や説明などプラグインに関する基本的な情報を取得する必要があります。 metadata.txt ファイルはこの情報を記載するのに適切な場所です。






name True


qgisMinimumVersion True


qgisMaximumVersion False


description True


about False


version True


author True


email True email of the author, will not be shown on the web site
changelog False


experimental False

ブール型のフラグ。 True または False

deprecated False

ブール型のフラグ。 True または False. アップロードされたバージョンだけではなくプラグイン全体に適用されます。

tags False comma separated list, spaces are allowed inside individual tags
homepage False


repository False


tracker False


icon False a file name or a relative path (relative to the base folder of the plugin’s compressed package)
category False

Raster, Vector, Database, Web のいずれか

By default, plugins are placed in the Plugins menu (we will see in the next section how to add a menu entry for your plugin) but they can also be placed the into Raster, Vector, Database and Web menus.

A corresponding “category” metadata entry exists to specify that, so the plugin can be classified accordingly. This metadata entry is used as tip for users and tells them where (in which menu) the plugin can be found. Allowed values for “category” are: Vector, Raster, Database or Web. For example, if your plugin will be available from Raster menu, add this to metadata.txt



qgisMaximumVersion が空の場合、 公式のpythonプラグインリポジトリ にアップロードされた時にメジャーバージョン + .99 に自動的に設定されます。

An example for this metadata.txt

; the next section is mandatory

[email protected]
author=Just Me
description=This is an example plugin for greeting the world.
    Multiline is allowed:
    lines starting with spaces belong to the same
    field, in this case to the "description" field.
    HTML formatting is not allowed.
about=This paragraph can contain a detailed description
    of the plugin. Multiline is allowed, HTML is not.
version=version 1.2
; end of mandatory metadata

; start of optional metadata
changelog=The changelog lists the plugin versions
    and their changes as in the example below:
    1.0 - First stable release
    0.9 - All features implemented
    0.8 - First testing release

; Tags are in comma separated value format, spaces are allowed within the
; tag name.
; Tags should be in English language. Please also check for existing tags and
; synonyms before creating a new one.
tags=wkt,raster,hello world

; these metadata can be empty, they will eventually become mandatory.

; experimental flag (applies to the single version)

; deprecated flag (applies to the whole plugin and not only to the uploaded version)

; if empty, it will be automatically set to major version + .99


This file is required by Python’s import system. Also, QGIS requires that this file contains a classFactory() function, which is called when the plugin gets loaded to QGIS. It receives reference to instance of QgisInterface and must return instance of your plugin’s class from the mainplugin.py — in our case it’s called TestPlugin (see below). This is how __init__.py should look like

def classFactory(iface):
  from mainPlugin import TestPlugin
  return TestPlugin(iface)

## any other initialisation needed


This is where the magic happens and this is how magic looks like: (e.g. mainPlugin.py)

from PyQt4.QtCore import *
from PyQt4.QtGui import *
from qgis.core import *

# initialize Qt resources from file resources.py
import resources

class TestPlugin:

  def __init__(self, iface):
    # save reference to the QGIS interface
    self.iface = iface

  def initGui(self):
    # create action that will start plugin configuration
    self.action = QAction(QIcon(":/plugins/testplug/icon.png"), "Test plugin", self.iface.mainWindow())
    self.action.setWhatsThis("Configuration for test plugin")
    self.action.setStatusTip("This is status tip")
    QObject.connect(self.action, SIGNAL("triggered()"), self.run)

    # add toolbar button and menu item
    self.iface.addPluginToMenu("&Test plugins", self.action)

    # connect to signal renderComplete which is emitted when canvas
    # rendering is done
    QObject.connect(self.iface.mapCanvas(), SIGNAL("renderComplete(QPainter *)"), self.renderTest)

  def unload(self):
    # remove the plugin menu item and icon
    self.iface.removePluginMenu("&Test plugins", self.action)

    # disconnect form signal of the canvas
    QObject.disconnect(self.iface.mapCanvas(), SIGNAL("renderComplete(QPainter *)"), self.renderTest)

  def run(self):
    # create and show a configuration dialog or something similar
    print "TestPlugin: run called!"

  def renderTest(self, painter):
    # use painter for drawing to map canvas
    print "TestPlugin: renderTest called!"

The only plugin functions that must exist in the main plugin source file (e.g. mainPlugin.py) are:

  • __init__ –> which gives access to QGIS interface
  • initGui() –> called when the plugin is loaded
  • unload() –> called when the plugin is unloaded

You can see that in the above example, the addPluginToMenu() is used. This will add the corresponding menu action to the Plugins menu. Alternative methods exist to add the action to a different menu. Here is a list of those methods:

  • addPluginToRasterMenu()
  • addPluginToVectorMenu()
  • addPluginToDatabaseMenu()
  • addPluginToWebMenu()

それらはすべて addPluginToMenu() メソッドと同じ構文です。


def initGui(self):
    self.menu = QMenu(self.iface.mainWindow())

    self.action = QAction(QIcon(":/plugins/testplug/icon.png"), "Test plugin", self.iface.mainWindow())
    self.action.setWhatsThis("Configuration for test plugin")
    self.action.setStatusTip("This is status tip")
    QObject.connect(self.action, SIGNAL("triggered()"), self.run)

    menuBar = self.iface.mainWindow().menuBar()
    menuBar.insertMenu(self.iface.firstRightStandardMenu().menuAction(), self.menu)

def unload(self):

Don’t forget to set QAction and QMenu objectName to a name specific to your plugin so that it can be customized.


You can see that in initGui() we’ve used an icon from the resource file (called resources.qrc in our case)

  <qresource prefix="/plugins/testplug" >

It is good to use a prefix that will not collide with other plugins or any parts of QGIS, otherwise you might get resources you did not want. Now you just need to generate a Python file that will contain the resources. It’s done with pyrcc4 command

pyrcc4 -o resources.py resources.qrc

And that’s all... nothing complicated :)

If you’ve done everything correctly you should be able to find and load your plugin in the plugin manager and see a message in console when toolbar icon or appropriate menu item is selected.



プラグインのドキュメントはHTMLヘルプファイルとして記述できます。 qgis.utils モジュールは他のQGISのヘルプと同じ方法でヘルプファイルブラウザを開く showPluginHelp() 関数を提供しています。

The showPluginHelp`() function looks for help files in the same directory as the calling module. It will look for, in turn, index-ll_cc.html, index-ll.html, index-en.html, index-en_us.html and index.html, displaying whichever it finds first. Here ll_cc is the QGIS locale. This allows multiple translations of the documentation to be included with the plugin.

showPluginHelp() 関数は引数をとることができます。packageName引数はヘルプが表示されるプラグインを識別します。filename引数は検索しているファイル名の”index”を置き換えます。そしてsection引数はブラウザが表示位置を合わせるドキュメント内のHTMLアンカータグの名前です。